An uneventful and, more importantly, an uninteresting game involving Chelsea? Surely not.

For a long time the most colourful thing about an afternoon of alternating rain and sun in South Wales was a rainbow above the halfway line. That would not have bothered Roberto Di Matteo at the end of another hectic week, once Victor Moses headed the goal that was keeping his team on top of the Premier League. Then, with two minutes to play, Swansea’s Spanish midfielder Pablo Hernandez drove in an equaliser that left Manchester United, who had beaten Chelsea last Sunday, on top of the pile.

It was deserved reward for the Welsh side’s refusal to give up on their neat passing game, even if they sometimes fell into the trap of making it just too intricate. They gained greater momentum once Danny Graham was called off the substitutes’ bench after Moses had scored, allowing Michu to drop a little deeper into his more natural position. Equally deserved, it might be said, was Chelsea’s fate, given that they created so little, especially in the second half. Once the goal went in, they seemed to take it for granted that victory would be theirs.

Without Juan Mata, so often the midfield fulcrum, there had been a lackadaisical air about much of their work. Di Matteo showed his displeasure by removing the ineffective Oriel Romeu at half-time and sending on Ramires, who he had hoped to hold in reserve for Wednesday’s Champions’ League game at home to Shakhtar Donetsk.

The manager declined to admit that the performance was well below par, though he did agree that fatigue may be kicking in amid the twice-weekly schedule and international games. As to whether all the off-field drama that seems to surround Chelsea had any effect, he insisted: “I wouldn’t read anything into that.”

There was notable and possibly pointed praise for the referee, Kevin Friend, of whom Di Matteo said: “He did very well and kept the players calm and I congratulate him. It takes something out of the ordinary for my players to react.”

Swansea’s Michael Laudrup, whose son Andreas recently played for Nordsjaelland in Chelsea’s flattering 4-0 win over them, was delighted, all the more so since there had been rumblings about discontent from some of his players earlier in the season. That was before a run of games against Manchester City, Liverpool (both away) and Chelsea that have brought a win, a draw and a defeat. “It’s three very good performances from the team in a great week for the club,” he said. “We played the champions of Europe and Liverpool at Anfield and I only counted five or six chances. Their goal today was a little lucky and it was a deserved point for us.”

Not only Mata was missing from the Chelsea midfield that has been so effective for most of the season but Frank Lampard too, and John Terry in defence. David Luiz, less critically, was injured, so Branislav Ivanovic and Gary Cahill played in the centre of the back four with Cesar Azpilicueta at right-back. Between them they kept the home side at bay with reasonable comfort, although the late goal means it is six games now without a clean sheet. Early on Hernandez sent the adventurous and poetic Angel Rangel clear but Ivanovic intercepted his cut-back and later Wayne Routledge set up Ki Sung-Yueng, Jon Obi Mikel making an important block.

If Mikel did not appear in any way affected by having been the central figure in last Sunday’s drama at Stamford Bridge, Romeu alongside him was poor and could not complain at being sent to the showers early. His countryman Fernando Torres had one of his better days, holding up the ball more reliably and winning several good headers. One of them brought just about the only excitement of the first half, when he headed Oscar’s corner towards the far post, Leon Britton clearing off the line.

Another Oscar corner led to the goal just after the hour, not without controversy. Britton was furious to be penalised for a tackle on the Brazilian, leading to a curling free-kick by Eden Hazard that the goalkeeper Gerhard Tremmel punched for a corner. From that, Cahill climbed highest for a solid header that Moses managed to flick on and in off a post for his first Chelsea goal in the League.

Laudrup brought on Graham and Nathan Dyer and the crowd awoke, too, and if the hymns and arias took on an increasingly desperate tone, they reached a crescendo as Ashley Cole lost possession, Swansea broke and the other substitute, Itay Shechter, laid the ball off for Hernandez to drive low inside a post.

“I know what Pablo can do,” Laudrup said. “Every foreigner needs time to adapt to this League and he’s getting better and better. You have a big sign on your shoulder saying ‘record signing’ [at £5.5 million] and so you have a little more pressure.” Hernandez wore it well.